The present invention relates generally to an electrolytic refining technique such as electrolytic copper refining. More particularly, the invention relates to a structure of an electric contact, for example, between an anode or a cathode and a bus bar (common conductor) or a side bus bar in an electrolytic cell used for electrolytic copper refining.
In the conventional art of, for example, electrolytic copper refining, anodes 1 comprising blister copper (99% Cu) and cathodes 2 serving as starting sheets are alternately arranged in parallel with each other as shown in FIG. 5 in a rectangular electrolytic cell.
A bus bar 10 is arranged on a wall of the electrolytic cell 100, and auricles 1A of prescribed anodes 1 prepared by casting blister copper and an end 3A of a crossbar (conducting rod) attached with prescribed cathodes 2 are arranged on the bus bar 10. A plurality of electrolytic cells 200 are usually arranged in parallel as shown in FIG. 6, and the anodes 1 and the cathodes 2 in the electrolytic cells are connected to a power source (+, -) by the current feeding method (Walker mode) as shown in FIG. 6.
It is known that, when carrying out electrolytic copper refining with the use of such an apparatus, the electrolytic efficiency decreases with the lapse of time. This is attributable to the fact that copper sulfate solution composing the electrolytic bath splashes to electric contact such as a space between the bus bar 10 and the electrode 1 (and the crossbar 3), resulting in precipitation of copper sulfate (CuSO.sub.4) at the contacts, thus causing an increase in contact resistance between the bus bar and the electrode. Such copper sulfate (CuSO.sub.4) adhering to the bus bar 10 or the like cannot be removed by simple water rinsing, requiring a polishing operation, this requiring much time and complicated operations for maintenance and management.
With a view to solving these problem, proposals have conventionally been made to adopt a special bus bar known as a wet bus bar in which a water-containing sponge is arranged on a bus bar, or to pass water through a hollow tubular bus bar, causing production of water drops on the bus bar surface to prevent formation of a copper sulfate (CuSO.sub.4) film at the contact, thus inhibiting an increase in contact resistance between the bus bar and the electrode. These measures cannot however be sufficient.